The US military is accusing ISIS of telling its fighters to pose as Iraqi soldiers and massacre civilians

Sunni
protesters at an anti-government rally in Fallujah, Iraq, in
2013.Bilal
Fawzi/AP

The US military unveiled
a document during a Pentagon press briefing on Tuesday that
officials say shows the terrorist group ISIS instructing its
fighters commit atrocities while posing as Iraqi
military forces before fleeing the city of Fallujah.

But some experts cast doubt the authenticity of the pamphlet,
cautioning that it could be a forgery by Shia militias
eager to disassociate themselves from atrocities
in Sunni areas.

The pamphlet, which was printed in Arabic and
translated into English after it was obtained by the US
military, says holding Fallujah has "become more harmful than
useful" for ISIS, which seized the Sunni-dominated city last year
and still holds control there.

"We realized that withdrawal is the right thing to do in the
event if the Army and the PMF will conduct assault on it," the
document says.

The pamphlet then instructs ISIS fighters to blow up mosques,
bomb civilian areas, set up snipers on high buildings, and kill
and torture civilians.

Fighters are told to dress similar to Shia militia fighters, who
are referred to as Popular Mobilization Forces, or
PMF, and Iraqi Security Forces. They're also asked to film
these acts, send the footage to Middle Eastern TV networks like
Al Jazeera, and claim they were carried out by Shia forces and
Iraqi Security Forces.

ISIS seems to hope that this will "incite the Sunnis' commotion
and grudge feelings" and make it seem as though the fight is
sectarian, according to the pamphlet.

Here's a look at the pamphlet:

Pentagon

Pentagon

"It's the behavior of thugs, it's the behavior of killers, it's
the behavior of terrorists," Col. Steven Warren, a spokesman for
the US-led anti-ISIS coalition, told reporters in a press
briefing on Tuesday.

Though ISIS is known for fanning the flames of sectarian
hatred to further its cause and attract new recruits, some
experts still doubted the document's authenticity. It's
unclear how exactly the US military verified that it
came from ISIS, which is also known as the Islamic State,
ISIL, or Daesh.

One inconsistency on the document can be seen on the top left
corner, which reads, "Ninawa Province." Fallujah is in Anbar
Province.

Michael Pregent, a former US Army intelligence officer who served
as an embedded military adviser in Iraq, told Business Insider
that he thought the document could be a Shia militia
forgery.

"ISIS isn't fleeing Fallujah now," Pregent said in an email.

Phillip Smyth, a researcher at the University of Maryland who
is a leading expert on Shia militias, also told Business
Insider he had doubts about the document's authenticity.

"Essentially, [the pamphlet] gives a sort of carte blanche for
sectarian Shia militias to continue engaging in vicious
activities and also gives cover to Iran's activities with those
groups in Iraq (given they back a large number of the groups
participating in the Fallujah offensive)," Smyth said.

Some of the allegations against Shia militias are recent. A man
named Ahmed, who has been fighting with Iraqi Special Operations
Forces to retake parts of Ramadi from ISIS,
told Vice News this week that he was tortured by a Shia
militia unit. The unit, known as the Golden Division, is the only
nonsectarian force in Iraq, made up of Sunni, Shia, Kurdish,
and Christian fighters, according to Vice.

Smyth pointed out that Shia militias have been known "for quite
some time" to carry out "ethnic cleansing, kidnappings, property
destruction, and executions" in Sunni areas. The US has been
criticized for working with these militias, which are said to
have a great deal of influence over the Iraqi central government
in Baghdad.

When asked at the briefing about the authenticity of the Fallujah
pamphlet, Warren said he believed it was "in fact
a legitimate document."

"It's certainly easy for me to believe it is in fact a legitimate
document because this is the type of behavior we're used to
seeing from these guys," Warren said, referring to ISIS.

Warren added, however, that he didn't have "any documented
examples of ISIS posing as Iraqi Security Forces and committing
atrocities yet."

The Pentagon didn't immediately respond to a request for
further comment.